The Challenge - Biomass Cooking Exacerbates Global Warming

Economic conditions force billions of people to burn biomass such as wood, charcoal, and dung to cook their food. These fires emit black carbon (a major component of soot), ozone- producing gases, methane and numerous other gases and particles that pollute indoor air. The soot from indoor smoke ultimately escapes to the outdoors and combines with other outdoor air pollution (fossil fuel combustion) to form atmospheric brown clouds (ABCs). ABCs contain sulfates, nitrates, soot and fly ash among many other pollutants. Soot and other particles in ABCs lead to a large reduction of sunlight at the ground and in addition lead to large atmospheric solar heating. The atmospheric solar heating by soot, next to carbon dioxide (CO2), is the major contributor to global warming.

Ozone Precursors

Biomass burning is also an important source of carbon monoxide (CO) and methane (CH4), two precursors for tropospheric, or ground-level ozone (O3). Ground-level ozone (unlike the "good ozone" in the upper atmosphere that shields us from the sun's rays) is a regional air pollutant than not only affects health but also significantly reduces crop yields. The interaction of the biofuel emissions with nitrogen oxides (NOx) and other emissions from India's power plants and growing transport fleet is leading to an increasing ozone burden in the region. 

Ozone's damaging effects on respiratory and cardiovascular health are well-established. It also exacerbates the symptoms of asthma. The pollutant is the trigger for Los Angeles' infamous "smog alerts." Ozone also has a significant effect on crop yields, especially for staple crops that India relies on. It is a powerful antioxidant, affecting plant cells as well as interfering with photosynthesis.

Conservative estimates for the yield loss for wheat, for example, are 7-12%, 6-16% for soybean, 3-4% for rice, and 3-5% for maize (Dingenen et al, 2009).  The portion of yield lost to ozone will increase over the coming decades unless mitigation measures are taken. Globally, the damages to crop yields were estimated at a staggering $14-26 billion for the year 2000. 

Moreover, since wood is one of the primary fuels used in burning of these fires, biomass cooking also leads to deforestation. Since trees store carbon, such deforestation in turn leads to greater atmospheric concentration of carbon dioxide (CO2).

Surya targets cooking with solid biomass fuels in rural India to reduce black carbon and ozone-precursor emissions, and can begin doing so almost immediately upon its launch.

Next: Water / Food Security